Heat sealing device



United States Patent O 3,116,393 HEAT SEAlLll'Nt-l- DEVlltCE Ernest G. Hachmeister, St. lbcnis, and Thomas .L Heiden,

dappington, Mo., assignors to industrial Engineering fr Equipment Co., St. Louis, Mo., a corporation of Missouri Filed Get. d, woll, Ser. No. 142,819 3 Claims. (SCE. 219-19) This invention relates generally to improvements in a heat sealing device, and more particularly to improvements in a package sealer adapted to close the seams of a package wrapped in any thermoplastic or other heat sensitive member by the utilization of a heat sealing element.

An important objective is to provide a ventilated, hushmounted package sealer.

it is an important object of the present invention to provide a heat sealing device that can be mounted and supported on a table section, and yet is so constructed that flammable material can be stored intentionally or therwise under the table section adjacent to the frame of the device, and in fact in contact with the accessible external portion of such frame, without creating a fire hazard.

r[he above mentioned functional advantages `are realized by the structural arrangement of the component parts oi the frame and the relative disposition of the heater unit in the frame, whereby the frame precludes any unintentional contact with the heater unit, and whereby the eX- ternal protective frame walls are cooled to an extent that any hre hazard is absolutely avoided.

An important objective is to afford a heat sealing device that can oe mounted in a wood table with its heat plate substa itialiy iiush with the table top, and yet obtain the lire safety features discussed previously.

Another important object is achieved by the mounting of the heat plate on a frame and by the provision of an air passage through the frame communicating with the region occupied by the heat plate, the air liow through the air passage being induced by the thermal eilfects created by the plate so that the cooler air is drawn over the external frame parts and subsequently discharged through a space provided about the periphery of the heat plate.

Yet another important objective is realized by the mounting of the heater unit on the frame, yet maintaining the heating plate in peripherally spaced relation to the trame, the frame including a pair of spaced walls about the heater unit, and means providing an air passage between the walls and communicating with the region occupied by the heater unit and the space between the frame and heater plate.

Still another important object is realized by constructing the frame of a pair of tubular member arranged in concentric, spaced relation, one within the other, by mounting the heating plate within the inner tubular member in peripherally spaced relation, and by providing an inlet between the tubular members at the top of such members. The members are open and communicate at their bottom ends for the flow of air from the space between the members up through the inner tubular member and out through the peripheral space between the heat plate and inner member.

Another important object is realized by depending a pair ci tubular members `from a top wall located substantially coplanar with the heat plate, the top wall being adapted 'for mounting iiush with a table section.

Other important advantages are achieved by extending the outer tubular member below the inner tubular member so as to increase the efciency of the induced air llow and to shield the other parts of the mounting frame.

An important object is to provide a heat sealing device that is simple and durable in construction, economical ICC to manufacture, eiicient in operation, and which can be utilized with the utmost safety.

The foregoing and numerous other objects and advantages of the invention will more clearly appear from the following detailed description of a preferred embodiment, particularly when considered in connection with the accompanying drawing in which:

PEG. l is a top plan view of the heat sealing device, and

PEG. 2 is a cross sectional view of `FlG. l.

E Lrring now by characters of reference to the drawing, it is seen that the heat sealing device includes a heater unit generally indicated at id mounted in a frame referred to at lill. This heat sealing device is usually mounted and supported in `a table indicated at i2 in order -to adapt the device for more effective use as a package sealer.

The heater unit litt includes a substantially flat hot plate i3 of substantially square configuration. The hot plate i3 is maintained in a substantially horizontal position. Of course, the hot plate llt` can be of any desired conguration to suit the needs and requirements or" a particular job or held of endeavor. in other words, the peripheral margin lli` of hot plate i3 is shown square in the present embodiment, 'but it will be readily realized that such margin i4 can be conveniently and advantageously made into any regular or irregular shape.

A cover iii is attached to the vunderside of heat plate i3, the cover i5 being spaced inwardly from the peripheral plate margin ifi. An electrical heating element id is retained within the cover i5 and is disposed in a pattern so as to distribute heat evenly to the superjacent plate Elfi. It will be realized that for best results in utilizing the package sealer, the heat plate i3 should be substantially the same temperature throughout the entire ilat surface over which a package wrapped in a thermoplastic material is `moved incident to sealing the seams of such wrapping.

Attached to the cover i5 is a `fitting E7. An electrical cable li is retained by the iitting 17 and is operatively connected to heating element i6. The cable 13' is operatively connected to a source of electrical power (not shown) in order to energize the heating element i6.

The frame lll includes a substantially horizontal, iiat top wall 2d of substantially square configuration as viewed in FG. l. rEhe top wall Ztl is` provided with a center opening Zit defined by a peripheral margin 22. rEhe heat pirate i3 is disposed in the center opening Ztl in substantially coplanar relation to the top wal-l Ztl. Importantly, the peripheral margin M of heat plate )t3 is maintained in spaced relation Ito the peripheral margin 22 of the top wall 2t* so as to eliminate the possibility of any transference of heat directly from the plate i3 to the frame ll.. The space 23 constitutes an outlet for an air passage that will be described and defined more fully upon later description of parts.

rl`he space 23 is of sumcient width to permit a tree how or air upwardly around the heat plate i3, and yet is not of a width so as not to interfere with the movement of packages of all sizes along the top wall 2G tonto the heat plate i3 and subsequently back onto the top wall 2t?. This sliding movement of packages is accomplished without requiring the package to be lifted at any time, and therefore it is seen that the space 213 is suiiiciently narrow so that the package wil-l not abut either of the margins 14 or 22. and thereby cause the package to be caught in the space 23.

A first tubular wall 2r?- is ormed integnally with the top lwall 2d and depends from wall 2d about the heater unit il?. The bottom end 2S of the lfirst tubular wall 2d is open and is spaced below the heater unit lil. As will be apparent, the thermal elifects created by the energization of the heat plate 13 will cause an up-draft through as seen along line 2 2 the iirst tubular wall 24. This induced air will enter the open bottom end 25 of the iirst tubular wall 24;-, tlow upwardly about the cover l', and thence will be discharged tio the atmosphere through the space Z3 at the periphery of the heat plate 13.

A pair of U-shaped brackets 126 tare disposed in supporting relation 4to the heater unit lil. The upper ends of the brackets 26 are liked as by welding to underside of wall Ztl andare spaced from the first tubular iwall 24. A pair of bol-ts 27 interconnect each bracket 26 ywith the heater unit le. A nut 2S xes each bolt 27 to the cover le', while a pair of coacting nuts 29 and 3l? secure each bolt 2,7 to its cooperating bracket 126. Upon selectively adjusting the Vnuts 23-3, the height of the heater unit l@ can be varied precisely in `order to maintain the top surface of plate 13 horizontal and in copianar relation to the top surface of wall 2li.

lt is seen that the brackets 26 and the mounting elements 2723i! support the heater unit lll in substantially insulated relation on the frame lll.

A second tubular wall 3l is formed integrally with the top wall 2u and depends from the top wall about the inner iii'st wall 221i. The iouter second wall 3l extends downwardly for a distance below the bottoni end Z5 of the inner first wall TA so as to shield the inner Wall 2.4 and the heater unit lil carried therein, and also to promote the inducement `of air how through the air passage previously mentioned. The outer second wall 3l is spaced laterally outward from the inner first wall 24 to provide a peripheral space 32 therebetween.

Of course, the tubular walls 24- and 31 are shown as square-shaped in n transverse plane as is seen best in FlG. l. Again it will be noted that the tubular walls `2d and 3l together with its connected top wall Ztl may be of any desired coniiguration, as for example, such parts could be circular or polygonal.

Provided in the top wall 2d are a plurality of elongate slots or openings 33 that communicate with the space 32 between the tubular walls 2d `and 3l. These slots 33 are provided about `the entire periphery of .the tubular walls 24 and Y3l and constitute an inlet to the air passage.

Sufficient structure of the frame has now been described in detail so las to enable the air passage to be defined. Considering the ow of air through such air passage, the air enters the space 3?; between walls 24 and 3l through the slots 33. This air ow continues downwardly to the bottom end 2.5 of the inner lirst wall 24, at which region, the lair flow is reversed so that it flows upwardly along the interior `of the inner tirst wall 24 about the heater unit lill. The air is discharged `from this passage through the space 23 at the periphery of the heat plate L13. Because the bottom end 3do the outer tubular wall 3l is spaced below the bottom end of the inner tubular wall 21%-, the flow of air downwardly through the space 32 is directed into the interior lof the inner wall Z4 rather than escaping to the outside of the second tubular wall 3l.

The top Wall Ztl is provided with a peripheral lip eX- tending laterally outward from the second tubular wall 3l. This lip 35 is formed substantially coplanar with the remaining portion of the top wall 2%, and consequently is coplanar with the heat plate i3. The lip 35 is utilized to mount the frame 11 on the table l2.

As is usual, the table i12 is provided with an aperture into which tihe `frame lil is tted, the table section 36 being provided with =a recessed channel into which the lip 35 seats. The depth of the channel closely approximates the thickness of `lip 35 so that the surface of table section 36 is substantially coplanar with the top wall 26.

It is thought that the operation and functional advantages of the heat sealing ydevice has become fully apparent from the foregoing detailed description of parts, but for completeness of disclosure, the ventilated feature of this flush mounted unit will be brieiiy described. It will be assumed that the heater unit lll is mounted to the irst tubular wall 24 and that the frame ll is mounted to the l table section 36 in the marmer previously described. The cable l@ is operatively connected to a source of electrical power and the heating element 116 is energized so as to heat the plate 13.

As plate ll heats the surrounding atmosphere, i.e., the immediately above the plate t3 and the volume of air contained within the tirst tubular Wall 24, the thermal etlect of such action is to cause an up-draft in the inner tubular wall 2d. This rip-draft immediately at the bottom end of the inner tubular wall Zd induces a downdratt in the space 32 between walls 2dand 3l. Consequently, cool air enters the slots 33 and moves downwardly in the space 32, thereby providing a moving tlow of cool air along the surface :of the outer tubular wall 3l constituting the external frame portion. The air flows along the passage and is introduced into the bottom of the inner' tubular wall 24, at which point the air is moved upwardly around the heater unit itl and is discharged at the atmosphere through the space 23 at the periphery of the heat plate l.

The top wall 2@ and the outer tubular wall 3l is cooled sutliciently by the ow of air so that the frame lt) can be safely mounted on a wooden table section 36 il desired. Moreover, material can be stored under the table section 3d close to the outer tubular wall 3l without creating any fire hazard because such wall 3l is at a greatly reduced temperature compared to the temperature of the heat plate 13 and its cover l5. This cool air flow prevents the external trame portions, that is to say tlie lip 35 and the outer tubular wall 33t, from reaching an excessive temperature while the plate t3 and cover l5 may reach 550 degrees F.

ln rising the heat sealing device, a package can be .'rapped in the thermoplastic material, and the package placed on the table section with the overlapping seams or the material face down. Then, the package can be simply slid over the table section 31,5, over the top plate Ztl and onto the heat plate ll3. The heat from plate i3 effectively seals the seams of the thermoplastic material very quickly, allowing the package to be slid in a continuous movement oil' of the plate and back onto the table section 36. lt is seen that the device is tlush mounted, and eliminates the necessity of lifting the package during this heat sealing movement.

Although the invention has been described by making detailed reference to a single preferred embodiment, such detail is to be understood in an instructive, rather than in any restrictive sense, many variants being possible within the scope of the claims hereunto appended.

We claim as our invention:

l. A heat sealing device comprising a flat plate, means for heating said plate, a frame having a top wall substantially coplanar with said plate, said top wall being disposed about yet spaced from the periphery of said plate, a rst tubular wall depending from said top wall, a second tubular wall depending from said top wall, said tubular walls providing a space therebetween, the top wall being provided with an opening communicating with the space between said tubular walls, said tubular walls communicating at their lower ends to provide an air passage the inlet of which is the opening of the space between said tubular members and the outlet of which is the space about the plate.

2. A heat sealing device comprising a heater unit having a at plate, means for heating said plate, a trame having a top wall substantially coplanar with said plate, said top wall being disposed about yet spaced from the periphery of said plate, a rst tubular wall depending from said top wall, means supporting the heater unit on said frame, a second tubular wall depending from said top wall, said tubular walls providing a space therebetween, the top wall being provided with an opening communicating with the space between said tubular walls, the second tubular wall extending a distance below the first tubular wall, said tubular walls communicating at their lower ends to provide an air passage the inlet of which is the opening to the space between said tubular walls and the outlet of which is the space about the plate.

3. A heat sealing device comprising a flat plate, means for heating said plate, a frame having a substantially horizontal top wall substantially eoplanar with said plate, said top wall being provided with an opening the peripheral margin of which is located about yet spaced from the periphery of said plate, a rst tubular wall depending from said top wall, said first tubular wall being open at the bottom, means supporting the plate on said frame, a second tubular wall depending from said top wall, said tubular walls providing a space therebetween, said second tubular wall being open at the bottom and extending a distance below said first tubular wall to protect and pre- 15 2,775,677

6 clude blockage of the open bottom of said first tubular wall, said top wall being provided with a plurality of openings communicating with lthe space between said tubular walls, said openings being arranged about the periphery of said walls, said tubular walls providing an air passage the inlet of which are the openings to the space between said tubular walls and the outlet of which is the space about the plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,534,221 Kereher Apr. 21, 1925 2,496,654 Alsdorf Feb. 7, 1950 Schuetze Dec. 25, 1956 

1. A HEAT SEALING DEVICE COMPRISING A FLAT PLATE, MEANS FOR HEATING SAID PLATE, A FRAME HAVING A TOP WALL SUBSTANTIALLY COPLANAR WITH SAID PLATE, SAID TOP WALL BEING DISPOSED ABOUT YET SPACED FROM THE PERIPHERY OF SAID PLATE, A FIRST TUBULAR WALL DEPENDING FROM SAID TOP WALL, A SECOND TUBULAR WALL DEPENDING FROM SAID TOP WALL, SAID TUBULAR WALLS PROVIDING A SPACE THEREBETWEEN, THE TOP WALL BEING PROVIDED WITH AN OPENING COMMUNICATING WITH THE SPACE BETWEEN SAID TUBULAR WALLS, SAID TUBULAR WALLS COMMUNICATING AT THEIR LOWER ENDS TO PROVIDE AN AIR PASSAGE THE INLET OF WHICH IS THE OPENING OF THE SPACE BETWEEN SAID TUBULAR MEMBERS AND THE OUTLET OF WHICH IS THE SPACE ABOUT THE PLATE. 